Gas fired infrared radiation emitters are widely used in the pulp and paper industry for the drying of coatings on moving cellulosic webs. These emitters are well known; thus, for example, one such emitter is described in U.S. Pat. No. 5,820,361.
The prior art gas fired infrared radiation emitters often contain a radiating (reverberating, radiant) screen (or “grating”) which increases the radiant power output of the emitter while simultaneously protecting the primary radiating surface from contamination. An example of an emitter with a removable grating is disclosed in U.S. Pat. No. 5,820,361.
Radiant burners comprising a radiant burner plate and a screen are also known from e.g. U.S. Pat. No. 4,799,879 or EP0539278.
It is known in the field to use a reinforcing cross above the radiant screen in or to strengthen the radiant screen and increase its lifetime.
U.S. Pat. No. 6,514,071 describes a gas-fired infrared radiation emitter comprising a burner surface; a radiant screen and a frame structure on the screen to removably position and to strengthen the screen.
U.S. Pat. No. 5,989,013 describes a porous mat gas fired radiant burner panels utilizing improved reverberating screens. The purpose of these screens is to boost the overall radiant output of the burner relative to a burner using no screen and the same fuel-air flow rates. In one embodiment, the reverberating screen is fabricated from ceramic composite material, which can withstand higher operating temperatures than its metallic equivalent. In another embodiment of U.S. Pat. No. 5,989,013 the reverberating screen is corrugated. The corrugations add stiffness which helps to resist creep and thermally induced distortions due to temperature or thermal expansion coefficient differences. As an added benefit, it has been discovered that the corrugations further increase the radiant efficiency of the burner. In a preferred embodiment, the reverberating screen is both corrugated and made from ceramic composite material.
U.S. Pat. No. 3,122,197 discloses a radiant burner comprising a casting defining a cavity, one side of the casting having an opening formed therein, the remaining surface of the side defining a flat rim surrounding the opening, a venture tube connected, in fluid flow relation, to the interior of said cavity to convey gas and air thereto. A first flat, perforated member covering said opening, a second, flexible, perforated, combustion-sustaining member including a central portion which overlies the opening and the corresponding portion of the first member. The central portion is fabricated to provide a number of parallel, U-shaped formations which cover said opening. The biggest portion of some of the U-shaped formations having substantially line contact with the first member. The bight portions of the remaining U-shaped formations of the central portion are tangent to a plane spaced from, and parallel to, the plan of the first member. The distance between the planes is greater than the combined thickness of the first and second members. The disclosure includes means for detachably clamping the peripheries of both of the screens to the rim.
It has been common practice in radiant gas burners to join together a number of perforated tiles (e.g. perforated ceramic tiles) arranged in rows or a square to provide a unitary burner plate. Flexible joints between individual perforated tiles are known as well as rigid joints.
U.S. Pat. No. 3,439,996 for instance, relates to radiant gas burners constituted of assembled heat-insulating perforated refractory tiles or blocks. The tiles are joined side by side with a refractory jointing compound or tile cement which, upon hardening, bonds the tile together and holds them in assembled relationship much as bricks are bonded together by mortar.
A known problem of radiant gas burners relates to the efficiency and effectiveness of the radiant screens.